Thanks to Richard and Scott. Scott's suggestion worked
perfectly...once I figured out that "foo" wasn't a command
abbreviation.
I'm not familiar with starting a command with the underscore (as in -
_retrun hold foo - ), what is that underscore doing?
Likewise, I'm not familar with the colon after a command line (as in -
estimates esample: - ), what does that colon do there?
Thanks again.
-Doug

That is actually the command's name, _return. Type
help _return

I'm not sure why and when Stata chooses to start a command with _,
but I think they tend to be programmer commands that would not
normally be used interactively. As for the colon, type